Ebi, a Drosophila homologue of TBL1, regulates the balance between cellular defense responses and neuronal survival

Transducin β-like 1 (TBL1), a transcriptional co-repressor complex, is a causative factor for late-onset hearing impairments. Transcriptional co-repressor complexes play pivotal roles in gene expression by making a complex with divergent transcription factors. However, it remained to be clarified how co-repressor complex regulates cellular survival. We herein demonstrated that ebi, a Drosophila homologue of TBL1, suppressed photoreceptor cell degeneration in the presence of excessive innate immune signaling. We also showed that the balance between NF-κB and AP-1 is a key component of cellular survival under stress conditions. Given that Ebi plays an important role in innate immune responses by regulating NF-κB activity and inhibition of apoptosis induced by associating with AP-1, it may be involved in the regulation of photoreceptor cell survival by modulating cross-talk between NF-κB and AP-1.

Linked randomised controlled trials of face-to-face and electronic brief intervention methods to prevent alcohol related harm in young people aged 14-17 years presenting to Emergency Departments (SIPS junior)

BACKGROUND

Alcohol is a major global threat to public health. Although the main burden of chronic alcohol-related disease is in adults, its foundations often lie in adolescence. Alcohol consumption and related harm increase steeply from the age of 12 until 20 years. Several trials focusing upon young people have reported significant positive effects of brief interventions on a range of alcohol consumption outcomes. A recent review of reviews also suggests that electronic brief interventions (eBIs) using internet and smartphone technologies may markedly reduce alcohol consumption compared with minimal or no intervention controls. Interventions that target non-drinking youth are known to delay the onset of drinking behaviours. Web based alcohol interventions for adolescents also demonstrate significantly greater reductions in consumption and harm among 'high-risk' drinkers; however changes in risk status at follow-up for non-drinkers or low-risk drinkers have not been assessed in controlled trials of brief alcohol interventions.

DESIGN AND METHODS

The study design comprises two linked randomised controlled trials to evaluate the effectiveness and cost-effectiveness of two intervention strategies compared with screening alone. One trial will focus on high-risk adolescent drinkers attending Emergency Departments (Eds) and the other will focus on those identified as low-risk drinkers or abstinent from alcohol but attending the same ED. Our primary (null) hypothesis is similar for both trials: Personalised Feedback and Brief Advice (PFBA) and Personalised Feedback plus electronic Brief Intervention (eBI) are no more effective than screening alone in alcohol consumed at 12 months after randomisation as measured by the Time-Line Follow-Back 28-day version. Our secondary (null) hypothesis relating to economics states that PFBA and eBI are no more cost-effective than screening alone. In total 1,500 participants will be recruited into the trials, 750 high-risk drinkers and 750 low-risk drinkers or abstainers. Participants will be randomised with equal probability, stratified by centre, to either a screening only control group or one of the two interventions: single session of PFBA or eBI. All participants will be eligible to receive treatment as usual in addition to any trial intervention. Individual participants will be followed up at 6 and 12 months after randomisation.

DISCUSSION

The protocol represents an ambitious innovative programme of work addressing alcohol use in the adolescent population.

TRIAL REGISTRATION

ISRCTN45300218. Registered 5th July 2014.

An NRSF/REST-like repressor downstream of Ebi/SMRTER/Su(H) regulates eye development in Drosophila

The corepressor complex that includes Ebi and SMRTER is a target of epidermal growth factor (EGF) and Notch signaling pathways and regulates Delta (Dl)-mediated induction of support cells adjacent to photoreceptor neurons of the Drosophila eye. We describe a mechanism by which the Ebi/SMRTER corepressor complex maintains Dl expression. We identified a gene, charlatan (chn), which encodes a C2H2-type zinc-finger protein resembling human neuronal restricted silencing factor/repressor element RE-1 silencing transcription factor (NRSF/REST). The Ebi/SMRTER corepressor complex represses chn transcription by competing with the activation complex that includes the Notch intracellular domain (NICD). Chn represses Dl expression and is critical for the initiation of eye development. Thus, under EGF signaling, double negative regulation mediated by the Ebi/SMRTER corepressor complex and an NRSF/REST-like factor, Chn, maintains inductive activity in developing photoreceptor cells by promoting Dl expression.

The surveillance mechanism of the spindle position checkpoint in yeast

The spindle position checkpoint in Saccharomyces cerevisiae delays mitotic exit until the spindle has moved into the mother-bud neck, ensuring that each daughter cell inherits a nucleus. The small G protein Tem1p is critical in promoting mitotic exit and is concentrated at the spindle pole destined for the bud. The presumed nucleotide exchange factor for Tem1p, Lte1p, is concentrated in the bud. These findings suggested the hypothesis that movement of the spindle pole through the neck allows Tem1p to interact with Lte1p, promoting GTP loading of Tem1p and mitotic exit. However, we report that deletion of LTE1 had little effect on the timing of mitotic exit. We also examined several mutants in which some cells inappropriately exit mitosis even though the spindle is within the mother. In some of these cells, the spindle pole body did not interact with the bud or the neck before mitotic exit. Thus, some alternative mechanism must exist to coordinate mitotic exit with spindle position. In both wild-type and mutant cells, mitotic exit was preceded by loss of cytoplasmic microtubules from the neck. Thus, the spindle position checkpoint may monitor such interactions.